'Gay and lesbian identities are largely the product of homophobic prejudice and repression. They are a self-defence mechanism against homophobia… if one sexuality is not privileged over another, defining oneself as gay (or straight) will cease to be necessary and have no social relevance or significance.'

Tatchell goes on to argue that we are already seeing a shift in sexual behaviours: 'We already know, thanks to a host of sex surveys, that bisexuality is an fact of life and that even in narrow-minded, homophobic cultures, many people have a sexuality that is, to varying degrees, capable of both heterosexual and homosexual attraction.

'The vast majority of people will be open to the possibility of both opposite-sex and same-sex desires, regardless of whether they act upon them,' Tatchell concludes. 'They won't feel the need to label themselves (or others) as gay or straight because, in a future non-homophobic civilisation, no one will care who loves who. Love will transcend sexual orientation.'

Australian born but now UK-based, Tatchell has campaigned for human rights, democracy and lesbian, gay, bisexual and transgender equality since 1967. In 2009, he won Campaigner of the Year at the Observer Ethical Awards.